Previous work of this laboratory has demonstrated in monkeys that nicotine has powerful reinforcing characteristics by reducing the aggressive behavioral effects of noxious and aversive stimuli, while increasing attentional and performance factors necessary for the learning of new responses. Alternatively, the termination of nicotine ingestion by monkeys after chronic exposure produces increases in aggressive behavior following noxious stimulation. Experiments with humans by this laboratory have confirmed these animal studies. A series of experiments have demonstrated that the ingestion of either nicotine or cigarette smoke reduces the reflex behavioral responses correlated with aggression and anger that result from noxious stimulation while the termination of smoking after chronic inhalation results in increase in anger and aggressivity. Additional studies of this laboratory have demonstrated that the occurrence of noxious or aversive stimuli results in the development of oral ingestive behaviors and the addition of drugs to the ingested substances produces a prompt and accentuated increment in the ingestive performance which in turn may result in subsequent alteration of other reactions normally occurring to noxious stimuli, such as aggressive behavior. The present research proposal suggests a series of experiments with monkeys designed to establish how environmental stimuli modify the oral ingestion of nicotine, and how such ingestion results in the establishment of behavioral dependence both in the locale containing noxious stimuli as well as in home living cage environment and how also this dependence may alter normal emotional and productive behavioral performances. Experiments proposed with human smokers would, in laboratory settings, study how envvironmental events alter the rate and pattern of cigarette smoke inhalation and in natural settings further explore with these same subjects, how daily experiences enhance and detract from a program of phased cigarette smoking withdrawal which utilizes a sequence of progressive smoke dilution.